"There are an estimated 27 million people in the U.S. with thyroid problems," says Dr. Prasad Katta, an endocrinologist at Washington Hospital. "That's more than the number of people with diabetes and cardiovascular disease combined. Thyroid dysfunction, if left untreated, can affect different systems of the body, and can even be life-threatening on occasion. Effective treatments for thyroid disorders are available, though. Unfortunately, many people with thyroid problems - perhaps as many as half of them - have not been tested and diagnosed."

The 13th annual Thyroid Awareness Month campaign was recently observed to help educate people about thyroid function and encourage regular thyroid screenings. Sponsored by the American Academy of Clinical Endocrinologists and the American Thyroid Association, the theme of this year's campaign is "How's Your Thyroid? Who Needs to Know."

"The thyroid is a small endocrine gland located at the front of the neck," Dr. Katta explains. "It secretes two hormones - called T-3 and T-4 - that contribute to the proper functioning of various parts of the body. They are particularly important in controlling your body's metabolism and converting calories to energy. Thyroid problems occur when the thyroid produces either too little or too much of the hormones."

Dr. Katta notes there are four main categories of thyroid problems:* Hypothyroidism - The thyroid produces a low level of hormones, resulting in a slowing down of many body functions.* Hyperthyroidism - The thyroid produces excessive amounts of hormones, which can speed up body functions and cause other uncomfortable and perhaps disabling symptoms.* Thyroid nodules - Small growths on the thyroid gland that can have some effects on thyroid function, but are not usually cancerous.* Thyroid cancer - Tumors on the thyroid that can spread to other parts of the body.

Hypothyroidism

"Hypothyroidism is more common than hyperthyroidism," Dr. Katta says. "The symptoms of hypothyroidism are what we call 'nonspecific,' because they can be symptoms of various other diseases, too. Some of the symptoms can include fatigue, sore muscles, dry skin and hair, fairly rapid and substantial weight gain, constipation, heavy or irregular menstrual periods, forgetfulness and drowsiness.

"The causes of hypothyroidism can vary," he adds. "It could be the result of treatment for hyperthyroidism, or it may be caused by a condition called 'thyroiditis,' which is an inflammation of the thyroid gland. Some medications such as lithium or high doses of iodine can cause hypothyroidism. There also is a condition known as post-partum hypothyroidism that occurs in some women after childbirth. Most commonly, though, there is no apparent reason for hypothyroidism."

Treatment for hypothyroidism consists of hormone-replacement therapy with thyroid hormone called Levothyrxoine. "At first, the patient's thyroid hormone levels will need to be monitored frequently until a stable does is achieved," Dr. Katta says. "After the hormone levels are stable, the patient should be screened every six to 12 months."

Hyperthyroidism

The four main causes of hyperthyroidism, when there is an excess of thyroid hormones, include:* Graves' disease, an autoimmune disorder named after an Irish physician,* Goiter, a collection of multiple nodules in the thyroid,* A single nodule or lump in the thyroid that is producing more hormones than the body requires, and* Thyroiditis, an enlargement and inflammation of the thyroid gland that releases large amounts of thyroid hormones into the blood.

"Hyperthyroidism produces a different set of symptoms from hypothyroidism," Dr. Katta notes. "You might experience symptoms such as a fast or irregular heart beat, nervousness or irritability, rapid weight loss in spite of a voracious appetite, night sweats, inability to sleep, hair loss and trembling hands or other body tremors."

Hyperthyroidism may be treated with radioactive iodine, in either pill or liquid form. "The thyroid is the only gland in the body that absorbs iodine, which is found in some foods and iodized salt," Dr. Katta explains. "The iodine is used to produce the T-3 and T-4 hormones. Using radioactive iodine kills a part of the gland, reducing the amount of hormones produced. Some patients treated with radioactive iodine may subsequently become hypothyroid and require hormone replacement."

Other treatment options for hyperthyroidism include medications such as Tapazole and Propylthiouracil (PTU), or surgical removal of the thyroid with subsequent hormone replacement.

Thyroid Nodules

"Thyroid nodules are fairly common," Dr. Katta comments. "About four percent of women and one percent of men will develop them, and there is an increased risk of developing nodules as we age. There are not usually any symptoms with thyroid nodules, unless they develop into a goiter, which can cause problems with breathing and swallowing. The way nodules are usually detected is when you notice a lump on the throat. To rule out cancer, we would do a fine-needle biopsy guided by ultrasound. If cancer is ruled out, we generally would just follow the patient's progress to make sure the nodule is not growing. If the nodule is causing hyperthyroidism, though, we would use the same treatments as for other causes of hyperthyroidism."

Thyroid Cancer

"No cancer can be considered 'good,' but thyroid cancer is one of the 'best' cancers to have in terms of successful treatments," Dr. Katta remarks. "Thyroid cancer is easily curable if it is detected early and hasn't spread beyond the thyroid.

"We generally treat the cancer by surgically removing the thyroid," he adds. "Because we can't always remove all of the thyroid gland, we also may use radioactive iodine. Then we follow up with hormone replacement, using a higher dose than normal to suppress thyroid growth and return of cancerous cells. The patient should be screened every three to four months for the first year, and then every six months after that to ensure the cancer has not returned."

Dr. Katta encourages all adults to have regular thyroid function screenings every year. "It's a simple blood test," he notes, "but it can make a tremendous difference in the quality of your life."